dracut.8.asc

   1 DRACUT(8)
   2 =========
   3 :doctype: manpage
   4 :man source:   dracut
   5 :man manual:   dracut
   6
   7 NAME
   8 ----
   9 dracut - low-level tool for generating an initramfs image
  10
  11 SYNOPSIS
  12 --------
  13 *dracut* ['OPTION...'] [<image> [_<kernel version>_]]
  14
  15 DESCRIPTION
  16 -----------
  17
  18 Create an initramfs <image> for the kernel with the version <kernel version>.
  19 If <kernel version> is omitted, then the version of the actual running
  20 kernel is used. If <image> is omitted or empty, then the default location
  21 /boot/initramfs-<kernel version>.img is used.
  22
  23 dracut creates an initial image used by the kernel for preloading the block
  24 device modules (such as IDE, SCSI or RAID) which are needed to access the root
  25 filesystem, mounting the root filesystem and booting into the real system.
  26
  27 At boot time, the kernel unpacks that archive into RAM disk, mounts and uses it
  28 as initial root file system. All finding of the root device happens in this
  29 early userspace.
  30
  31 For a complete list of kernel command line options see *dracut.cmdline*(7).
  32
  33 EXAMPLE
  34 -------
  35
  36 To create a initramfs image, the most simple command is:
  37 ----
  38 # dracut
  39 ----
  40
  41 This will generate a general purpose initramfs image, with all possible
  42 functionality resulting of the combination of the installed dracut modules and
  43 system tools. The image is /boot/initramfs-_++<kernel version>++_.img and
  44 contains the kernel modules of the currently active kernel with version
  45 _++<kernel version>++_.
  46
  47 If the initramfs image already exists, dracut will display an error message, and
  48 to overwrite the existing image, you have to use the --force option.
  49 ----
  50 # dracut --force
  51 ----
  52
  53 If you want to specify another filename for the resulting image you would issue
  54 a command like:
  55 ----
  56 # dracut foobar.img
  57 ----
  58
  59 To generate an image for a specific kernel version, the command would be:
  60 ----
  61 # dracut foobar.img 2.6.40-1.rc5.f20
  62 ----
  63
  64 A shortcut to generate the image at the default location for a specific kernel
  65 version is:
  66 ----
  67 # dracut --kver 2.6.40-1.rc5.f20
  68 ----
  69
  70 If you want to create lighter, smaller initramfs images, you may want to specify
  71 the --host-only or -H option. Using this option, the resulting image will
  72 contain only those dracut modules, kernel modules and filesystems, which are
  73 needed to boot this specific machine. This has the drawback, that you can't put
  74 the disk on another controller or machine, and that you can't switch to another
  75 root filesystem, without recreating the initramfs image. The usage of the
  76 --host-only option is only for experts and you will have to keep the broken
  77 pieces. At least keep a copy of a general purpose image (and corresponding
  78 kernel) as a fallback to rescue your system.
  79
  80
  81 OPTIONS
  82 -------
  83 **--kver** _<kernel version>_::
  84     set the kernel version. This enables to specify the kernel version, without
  85     specifying the location of the initramfs image. For example:
  86 ----
  87 # dracut --kver 3.5.0-0.rc7.git1.2.fc18.x86_64
  88 ----
  89
  90 **-f, --force**::
  91     overwrite existing initramfs file.
  92
  93 **-m, --modules** _<list of dracut modules>_::
  94     specify a space-separated list of dracut modules to call when building the
  95     initramfs. Modules are located in _/usr/lib/dracut/modules.d_. This
  96     parameter can be specified multiple times.
  97 +
  98 [NOTE]
  99 ===============================
 100 If [LIST] has multiple arguments, then you have to put these in quotes. For
 101 example:
 102 ----
 103 # dracut --modules "module1 module2"  ...
 104 ----
 105 ===============================
 106
 107 **-o, --omit** _<list of dracut modules>_::
 108     omit a space-separated list of dracut modules. This parameter can be
 109     specified multiple times.
 110 +
 111 [NOTE]
 112 ===============================
 113 If [LIST] has multiple arguments, then you have to put these in quotes. For
 114 example:
 115 ----
 116 # dracut --omit "module1 module2"  ...
 117 ----
 118 ===============================
 119
 120 **-a, --add** _<list of dracut modules>_::
 121     add a space-separated list of dracut modules to the default set of modules.
 122     This parameter can be specified multiple times.
 123 +
 124 [NOTE]
 125 ===============================
 126 If [LIST] has multiple arguments, then you have to put these in quotes. For
 127 example:
 128 ----
 129 # dracut --add "module1 module2"  ...
 130 ----
 131 ===============================
 132
 133 **--force-add** _<list of dracut modules>_::
 134     force to add a space-separated list of dracut modules to the default set of
 135     modules, when -H is specified. This parameter can be specified multiple
 136     times.
 137 +
 138 [NOTE]
 139 ===============================
 140 If [LIST] has multiple arguments, then you have to put these in quotes. For
 141 example:
 142 ----
 143 # dracut --force-add "module1 module2"  ...
 144 ----
 145 ===============================
 146
 147 **-d, --drivers** _<list of kernel modules>_::
 148     specify a space-separated list of kernel modules to exclusively include
 149     in the initramfs. The kernel modules have to be specified without the ".ko"
 150     suffix. This parameter can be specified multiple times.
 151 +
 152 [NOTE]
 153 ===============================
 154 If [LIST] has multiple arguments, then you have to put these in quotes. For
 155 example:
 156 ----
 157 # dracut --drivers "kmodule1 kmodule2"  ...
 158 ----
 159 ===============================
 160
 161 **--add-drivers** _<list of kernel modules>_::
 162     specify a space-separated list of kernel modules to add to the initramfs.
 163     The kernel modules have to be specified without the ".ko" suffix. This
 164     parameter can be specified multiple times.
 165 +
 166 [NOTE]
 167 ===============================
 168 If [LIST] has multiple arguments, then you have to put these in quotes. For
 169 example:
 170 ----
 171 # dracut --add-drivers "kmodule1 kmodule2"  ...
 172 ----
 173 ===============================
 174
 175 **--omit-drivers** _<list of kernel modules>_::
 176     specify a space-separated list of kernel modules not to add to the
 177     initramfs.
 178     The kernel modules have to be specified without the ".ko" suffix. This
 179     parameter can be specified multiple times.
 180 +
 181 [NOTE]
 182 ===============================
 183 If [LIST] has multiple arguments, then you have to put these in quotes. For
 184 example:
 185 ----
 186 # dracut --omit-drivers "kmodule1 kmodule2"  ...
 187 ----
 188 ===============================
 189
 190 **--filesystems** _<list of filesystems>_::
 191     specify a space-separated list of kernel filesystem modules to exclusively
 192     include in the generic initramfs. This parameter can be specified multiple
 193     times.
 194 +
 195 [NOTE]
 196 ===============================
 197 If [LIST] has multiple arguments, then you have to put these in quotes. For
 198 example:
 199 ----
 200 # dracut --filesystems "filesystem1 filesystem2"  ...
 201 ----
 202 ===============================
 203
 204 **-k, --kmoddir** _<kernel directory>_::
 205     specify the directory, where to look for kernel modules
 206
 207 **--fwdir** _<dir>[:<dir>...]++_::
 208     specify additional directories, where to look for firmwares. This parameter
 209     can be specified multiple times.
 210
 211 **--kernel-cmdline <parameters>**::
 212     specify default kernel command line parameters
 213
 214
 215 **--kernel-only**::
 216     only install kernel drivers and firmware files
 217
 218 **--no-kernel**::
 219     do not install kernel drivers and firmware files
 220
 221 **--mdadmconf**::
 222     include local _/etc/mdadm.conf_
 223
 224 **--nomdadmconf**::
 225     do not include local _/etc/mdadm.conf_
 226
 227 **--lvmconf**::
 228     include local _/etc/lvm/lvm.conf_
 229
 230 **--nolvmconf**::
 231     do not include local _/etc/lvm/lvm.conf_
 232
 233 **--fscks** [LIST]::
 234     add a space-separated list of fsck tools, in addition to _dracut.conf_'s
 235     specification; the installation is opportunistic (non-existing tools are
 236     ignored)
 237 +
 238 [NOTE]
 239 ===============================
 240 If [LIST] has multiple arguments, then you have to put these in quotes. For
 241 example:
 242 ----
 243 # dracut --fscks "fsck.foo barfsck"  ...
 244 ----
 245 ===============================
 246
 247 **--nofscks**::
 248     inhibit installation of any fsck tools
 249
 250 **--strip**::
 251     strip binaries in the initramfs
 252
 253 **--nostrip**::
 254     do not strip binaries in the initramfs (default)
 255
 256 **--hardlink**::
 257     hardlink files in the initramfs (default)
 258
 259 **--nohardlink**::
 260     do not hardlink files in the initramfs
 261
 262 **--prefix** _<dir>_::
 263     prefix initramfs files with the specified directory
 264
 265 **--noprefix**::
 266     do not prefix initramfs files (default)
 267
 268 **-h, --help**::
 269     display help text and exit.
 270
 271 **--debug**::
 272     output debug information of the build process
 273
 274 **-v, --verbose**::
 275     increase verbosity level (default is info(4))
 276
 277 **-q, --quiet**:: decrease verbosity level (default is info(4))
 278
 279 **-c, --conf** _<dracut configuration file>_::
 280     specify configuration file to use.
 281 +
 282 Default:
 283    _/etc/dracut.conf_
 284
 285 **--confdir** _<configuration directory>_::
 286     specify configuration directory to use.
 287 +
 288 Default:
 289    _/etc/dracut.conf.d_
 290
 291 **--tmpdir** _<temporary directory>_::
 292     specify temporary directory to use.
 293 +
 294 Default:
 295    _/var/tmp_
 296
 297 **--sshkey** _<sshkey file>_:: ssh key file used with ssh-client module.
 298
 299 **-l, --local**::
 300     activates the local mode. dracut will use modules from the current working
 301     directory instead of the system-wide installed modules in
 302     _/usr/lib/dracut/modules.d_.
 303     This is useful when running dracut from a git checkout.
 304
 305 **-H, --hostonly**::
 306     Host-Only mode: Install only what is needed for booting the local host
 307     instead of a generic host and generate host-specific configuration.
 308 +
 309 [WARNING]
 310 ====
 311 If chrooted to another root other than the real root device, use "--fstab" and
 312 provide a valid _/etc/fstab_.
 313 ====
 314
 315 **-N, --no-hostonly**::
 316     Disable Host-Only mode
 317
 318 **--fstab**::
 319     Use _/etc/fstab_ instead of _/proc/self/mountinfo_.
 320
 321 **--add-fstab** _<filename>_ ::
 322     Add entries of _<filename>_ to the initramfs /etc/fstab.
 323
 324 **--mount** "_<device>_ _<mountpoint>_ _<filesystem type>_ _<filesystem options>_"::
 325     Mount _<device>_ on _<mountpoint>_ with _<filesystem type>_ and _<filesystem
 326     options>_ in the initramfs
 327
 328 **--device** _<device>_ ::
 329     Bring up _<device>_ in initramfs, _<device>_ should be the device name
 330
 331 **-i, --include** _<SOURCE>_ _<TARGET>_::
 332     include the files in the SOURCE directory into the
 333     TARGET directory in the final initramfs. If SOURCE is a file, it will be
 334     installed to TARGET in the final initramfs. This parameter can be specified
 335     multiple times.
 336
 337 **-I, --install** _<file list>_::
 338     install the space separated list of files into the initramfs.
 339 +
 340 [NOTE]
 341 ===============================
 342 If [LIST] has multiple arguments, then you have to put these in quotes. For
 343 example:
 344 ----
 345 # dracut --install "/bin/foo /sbin/bar"  ...
 346 ----
 347 ===============================
 348
 349 **--gzip**::
 350     Compress the generated initramfs using gzip. This will be done by default,
 351     unless another compression option or --no-compress is passed. Equivalent to
 352     "--compress=gzip -9"
 353
 354 **--bzip2**::
 355     Compress the generated initramfs using bzip2.
 356 +
 357 [WARNING]
 358 ====
 359 Make sure your kernel has bzip2 decompression support compiled in, otherwise you
 360 will not be able to boot. Equivalent to "--compress=bzip2"
 361 ====
 362
 363 **--lzma**::
 364     Compress the generated initramfs using lzma.
 365 +
 366 [WARNING]
 367 ====
 368 Make sure your kernel has lzma decompression support compiled in, otherwise you
 369 will not be able to boot. Equivalent to "--compress=lzma -9"
 370 ====
 371
 372 **--xz**::
 373     Compress the generated initramfs using xz.
 374 +
 375 [WARNING]
 376 ====
 377 Make sure your kernel has xz decompression support compiled in, otherwise you
 378 will not be able to boot. Equivalent to "--compress=xz --check=crc32
 379 --lzma2=dict=1MiB"
 380 ====
 381
 382 **--compress** _<compressor>_::
 383     Compress the generated initramfs using the passed compression program. If
 384     you pass it just the name of a compression program, it will call that
 385     program with known-working arguments. If you pass a quoted string with
 386     arguments, it will be called with exactly those arguments. Depending on what
 387     you pass, this may result in an initramfs that the kernel cannot decompress.
 388
 389 **--no-compress**::
 390     Do not compress the generated initramfs. This will override any other
 391     compression options.
 392
 393 **--list-modules**::
 394     List all available dracut modules.
 395
 396 **-M, --show-modules**::
 397     Print included module's name to standard output during build.
 398
 399 **--keep**::
 400     Keep the initramfs temporary directory for debugging purposes.
 401
 402 FILES
 403 -----
 404 _/var/log/dracut.log_::
 405     logfile of initramfs image creation
 406
 407 _/tmp/dracut.log_::
 408     logfile of initramfs image creation, if _/var/log/dracut.log_ is not
 409     writable
 410
 411 _/etc/dracut.conf_::
 412     see dracut.conf5
 413
 414 _/etc/dracut.conf.d/*.conf_::
 415     see dracut.conf5
 416
 417 Configuration in the initramfs
 418 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 419 _/etc/conf.d/_::
 420     Any files found in _/etc/conf.d/_ will be sourced in the initramfs to
 421     set initial values. Command line options will override these values
 422     set in the configuration files.
 423
 424 _/etc/cmdline_::
 425     Can contain additional command line options. Deprecated, better use /etc/cmdline.d/*.conf.
 426
 427 _/etc/cmdline.d/*.conf::
 428     Can contain additional command line options.
 429
 430 AVAILABILITY
 431 ------------
 432 The dracut command is part of the dracut package and is available from
 433 link:$$https://dracut.wiki.kernel.org$$[https://dracut.wiki.kernel.org]
 434
 435 AUTHORS
 436 -------
 437 Harald Hoyer
 438
 439 Victor Lowther
 440
 441 Philippe Seewer
 442
 443 Warren Togami
 444
 445 Amadeusz Żołnowski
 446
 447 Jeremy Katz
 448
 449 David Dillow
 450
 451 Will Woods
 452
 453 SEE ALSO
 454 --------
 455 *dracut.cmdline*(7) *dracut.conf*(5)